Recently, a vehicle equipped with a solar power generating device on a roof or the like has been proposed. Driving environment of the vehicle of this type is desirably efficiency. For example, Patent Document 1 proposes a system for providing power generation information of the vehicle equipped with a solar power generating device to the user. The system includes a power generation information request device used in the vehicle equipped with the solar power generating device. The power generation information request device correlates power generation amount of the solar power generating device with position and time of the vehicle to generate probe information, and transmits the probe information. A center collects the probe information transmitted from an unspecified number of the power generation information request device. The center generates information indicating a route and time zone efficient for power generation, information indicating a position in the parking lot efficient for power generation, and the like based on the collected probe information and weather information obtained from the external service unit. The center provides this information to the power generation information request device.